Abstract: A plug device may be for a swimming pool fence system that includes spaced apart vertical fence posts to be inserted into corresponding fence post openings in a pool deck, and a fencing material coupled between adjacent spaced apart vertical fence posts. The plug device may include a cylindrical body having opposing first and second ends. The first end may be adjacent a distal end of a respective fence post opening in the pool deck upon insertion therein. The plug device may include a magnet carried by the second end of the cylindrical body. The plug device may also include a cylindrical pool deck cap carried by the magnet. The cylindrical pool deck cap may be adjacent a proximal end of the respective fence post opening in the pool deck upon insertion therein.